The present invention relates to a gas chromatography/mass spectrometry system that includes a gas chromatograph and a mass spectrometer.
Recently, gas chromatography/mass spectrometry systems (“GC/MS”) combining gas chromatographs and mass spectrometers have been widely used for identification analysis and quantification analysis of various kinds of samples. See, for example, the system disclosed in Japanese Unexamined Patent Publication No. H10-283982.
In a GC/MS, when introducing sample gases into the column of the GC part, various kinds of sample introduction devices are used in accordance with the types and properties of the samples. For example, when analyzing agricultural chemicals, and in environmental analyses, a liquid sample introduction device is used which gasifies the liquefied sample inside a high-temperature sample gasification chamber and sends it into the column.
Also, when analyzing volatile organic compounds (“VOC”), such as trichloroethylene, and the like, a headspace sample introduction device is used. The headspace sample introduction device collects a specified quantity of sample gas volatized from a liquid sample stored in a container, and sends the volatized gas to the column.
Also, because it is necessary to also change the separation properties of the columns used for component analysis between agricultural chemicals and volatile organic compounds, the columns that are used are themselves different when using a liquid sample introduction device and when using a headspace sample introduction device.
Therefore, in an organization that must analyze both agricultural chemicals and volatile organic compounds, such as environmental analysis research institutions, it is desirable to have a GC/MS having a liquid sample introduction device and an associated column suitable for agricultural chemical analysis, and a GC/MS having a headspace sample introduction device and an associated column suitable for volatile organic compound analysis. Then, the systems can be prepared respectively in advance, and the analysis can be performed by selecting either device in accordance with the sample to be analyzed.
However, because preparing two GC/MS's is expensive, a conventional approach has been to perform agricultural chemical analysis and volatile organic compound analysis by suitably switching with one GC/MS. In the past, although there have been gas chromatography devices configured such that a liquid sample introduction device and a headspace sample introduction device can be arranged in parallel, it was still necessary to attach a column suitable for the respective analysis. That is, depending on whether a liquid sample introduction device or a headspace sample introduction device is used, it was necessary to attach a column between the sample gas outlet end of the liquid sample introduction device or the headspace sample introduction device, and a GC/MS interface.
Therefore, when switching, for example, from agricultural chemical analysis to volatile organic compound analysis, it has been necessary to replace the column inside the column oven. This is done by temporarily stopping the device and returning the vacuum chamber of the mass spectrometer to approximately atmospheric pressure. Such operations take effort and time, and the analytical efficiency is degraded. Also, as a result of repeated stopping and starting of the device, instabilities easily arise. For example, the inside of the vacuum chamber of the mass spectrometer may be contaminated by components in the air, and the reliability of analysis may be lowered.
Also, when analyzing volatile organic compounds in water, a purge/trap sample introduction device also may be used in place of the headspace sample introduction device. A purge/trap sample introduction device forcefully drives out volatile organic compounds and mold odors, and the like, in the water by blowing purge gas into a custom test tube in which sample water is collected, and temporarily retains the driven-out components in an adsorbent material. After that, the sample components are separated from the adsorbent material by heating them off, and they are then introduced into the column. Also, when it is desirable to selectively use such a sample introduction device with a liquid sample introduction device or headspace sample introduction device, the same problems as those described above also arise.
The present invention addresses the aforementioned problems associated with the prior art devices.
One object of the present invention is to provide a gas chromatography/mass spectrometry system that can perform analysis of samples of different kinds and different properties, such as analysis of agricultural chemicals, and the like, and analysis of volatile organic compounds, and the like, with one system using columns suitable for each.
Another object of the present invention is to provide a gas chromatography/mass spectrometry system that can perform the above-described two kinds of analysis continuously without requiring the annoying work of changing columns, and without temporarily stopping the device.
Further objects and advantages of the invention will be apparent from the following description of the invention and the associated drawings.